現(xiàn)有: class A {public String name="a"} class B extends A {public String name="b"} 執(zhí)行如下代碼后的結(jié)果是哪項(xiàng)?() A a=new B(); System.out.println(a.name);
A. a B. b C.編譯失敗 D.運(yùn)行時(shí)拋出異常
現(xiàn)有: class TestA { public void start() { System.out.println("TestA"); } } public class TestB extends TestA { public void start() { System.out.println("TestB"); } public static void main (string[] args) ( ((TestA)new TestB()).start(); ) } 運(yùn)行結(jié)果是哪項(xiàng)?()
A. TeStA B. TeStB C.編譯失敗 D.運(yùn)行時(shí)拋出異常
現(xiàn)有: class Pencil { public void write (String content){ System.out.println( "Write",+content){ } }class RubberPencil extends Pencil{ public void write (String content){ System.out.println("Rubber Write"+content); } public void erase (String content)}} 執(zhí)行下列代碼的結(jié)果是哪項(xiàng)?() Pencil pen=new Pencil(); (( RubberPencil) pen).write( "Hello");
A.Write Hello B.Rubber Write Hello C.編譯失敗 D.運(yùn)行時(shí)拋出異常